The 50 most-cited articles in Journal of The Electrochemical Society, 2024

Recent battery papers commonly employ interpretation models for which diffusion impedances are in series with interfacial impedance. The models are fundamentally flawed because the diffusion impedance is inherently part of the interfacial impedance. A derivation for faradaic impedance is presented which shows how the charge-transfer resistance and diffusion resistance are functions of the concentration of reacting species at the electrode surface, and the resulting impedance model incorporates diffusion impedances as part of the interfacial impedance. Conditions are identified under which the two model formulations yield the same results. These conditions do not apply for batteries.

The trend for increased nickel content in layered transition metal oxide cathode active materials and increasing charging cut-off voltages aggravates aging of lithium-ion battery cells at high state of charge (SOC). We investigate the calendaric aging behavior of large-format automotive prototype cells and laboratory single-layer pouch cells at high but realistic cell voltages/SOCs and demonstrate that electrolyte oxidation in combination with follow-up reactions can cause a significant loss of the LiPF6 salt in the electrolyte. For this, we analyze the LiPF6 concentration in aged cells, the generation of H2 upon storage, and the cell resistance for different aging conditions. We show that the LiPF6 loss is a critical aging phenomenon, as it cannot readily be detected by capacity fading measurements at low/medium C-rates or by cell resistance measurements, while it severely reduces rate and fast-charging capability. Under certain circumstances, LiPF6 loss can even lead to a temporary capacity increase due to conversion of the conducting salt in the electrolyte to cyclable lithium in…

The rate of electric vehicle (EV) adoption, powered by the Li-ion battery, has grown exponentially; largely driven by technological advancements, consumer demand, and global initiatives to reduce carbon emissions. As a result, it is imperative to understand the state of stability (SoS) of the cells inside an EV battery pack. That understanding will enable the warning of or prevention against catastrophic failures that can lead to serious injury or even, loss of life. The present work explores rapid electrochemical impedance spectroscopy (EIS) coupled with gas sensing technology as diagnostics to monitor cells and packs for failure markers. These failure markers can then be used for onboard assessment of SoS. Experimental results explore key changes in single cells and packs undergoing thermal or electrical abuse. Rapid EIS showed longer warning times, followed by VOC sensors, and then H 2 sensors. While rapid EIS gives the longest warning time, with the failure marker often appearing before the cell vents, the reliability of identifying impedance changes in single cells within a…

In this work, ≈25 μm thin titanium microporous layers (MPLs) with ≈2 μm small pores and low surface roughness were coated and sintered on top of ≈260 μm thick commercial titanium-powder-sinter sheets with ≈16 μm pores, maintaining a porosity of ≈40% in both layers. Serving as porous transport layers (PTLs) on the anode side in proton exchange membrane water electrolyzers (PEMWEs), these pore-graded, two-layer sheets (“PTL/MPL”) are compared to single-layer PTLs in single-cell PEMWEs. The PTL/MPL samples prepared here give a 3–6 mΩ cm2 lower high-frequency resistance (HFR) compared to the as-received single-layer PTL, which is attributed to a partial reduction of the TiO2 surface passivation layer during the MPL sintering process. For ≈1 μm thin anodes with an iridium loading of ≈0.2 mgIr cm−2, the use of an MPL leads to a ≈24 mV improvement in HFR-free cell voltage at 6 A cm−2. As no such benefit is observed for ≈9 μm thick anodes with ≈2.0 mgIr cm−2, mass transport resistances within the PTL/MPL play a minor role. Possible reasons for the higher catalyst utilization in ultra-thin…

Water contaminants are a common cause of failure for polymer electrolyte membrane (PEM) electrolyzers in the field as well as a confounding factor in research on cell performance and durability. In this study, we investigated the performance impacts of feed water containing representative tap water cations at concentrations ranging from 0.5–500 μ M, with conductivities spanning from ASTM Type II to tap-water levels. We present multiple diagnostic signatures to help identify the presence of contaminants in PEM electrolysis cells. Through analysis of polarization curves and impedance spectroscopy to understand the origins of performance losses, we found that a switch from the acidic to alkaline hydrogen evolution mechanism is a key factor in contaminated cell behavior. Finally, we demonstrated that this mechanism switching can be harnessed to remove cation contaminants and recover cell performance without the use of an acid wash. We demonstrated near-complete recovery of cells contaminated with sodium and calcium, and partial recovery of a cell contaminated with iron, which was…

The thermal safety of lithium-ion (Li-ion) batteries for electric vehicles continues to remain a major concern. A comprehensive understanding of the thermal runaway (TR) mechanisms in Li-ion cells and modules due to intrinsic factors such as state-of-charge (SOC) and cell-to-cell arrangement under abuse scenarios such as external heating is critical toward the development of advanced battery thermal management systems. This study presents a hierarchical TR modeling framework to examine the TR behavior of Li-ion cells at various SOCs and probe its implications on the thermal runaway propagation (TRP) in a battery module. We perform accelerating rate calorimetry (ARC) experiments with 3.25 Ah cylindrical Li-ion cells at different SOCs and demonstrate the strong SOC dependence of TR characteristics such as the onset temperature, maximum cell temperature, and self-heating rate. The thermo-kinetic parameters extracted from the ARC experiments are used to develop a TR model that captures the SOC-induced TR response in Li-ion cells. The mechanistic information from the cell-level model is…

One Health is a comprehensive and cohesive strategy that seeks to effectively manage and enhance the well-being of people, animals, and ecosystems in a sustainable manner. Electrochemical biosensors are indispensable vectors for One Health management, with diverse applications across industrial process control, environmental monitoring, healthcare, microbiology, and quality assurance. The integration of nanotechnology has propelled innovative sensing algorithms, enhancing the efficiency and precision of biosensors. Nanoscale material integration amplifies their ability to detect molecules and single biomolecules with nano-biosensors utilizing nanoparticles, nanowires, carbon nanotubes (CNTs), nanorods, and quantum dots. Nanomaterials, distinguished by surface functionalities, tunability of physical/chemical properties, high detection sensitivity, large surface area, stability, and thermal/electrical conductivity, are instrumental in architecting nano-biosensors. The main limitations in current times are scalability, cross-sensitivity, complex immobilization pathways, and the…

Considering the growing need for extensive energy storage solutions in smart grid technologies and affordable options for entry-level electric vehicles, sodium-ion batteries offer a promising alternative. They use raw materials that are cheaper, less toxic, and more abundant than those used in lithium-ion batteries, making them especially suitable for large-scale applications. This study comprehensively investigated four commercially available sodium-ion batteries to examine their structural and electrochemical characteristics. The cells were dissected, and the electrode dimensions, the areal mass loadings, and the material compositions were analyzed using scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and attenuated total reflection Fourier-transform infrared spectroscopy. Electrical characterization, including electrochemical impedance spectroscopy, C-rate testing up to 6 C under different ambient temperatures, along with cyclic aging studies, provided insights into the cells’ performance and degradation mechanisms. The findings…

The kinetics of composite cathodes for solid-state batteries (SSBs) relies heavily on their microstructure. Spatial distribution of the different phases, porosity, interface areas, and tortuosity factors are important descriptors that need accurate quantification for models to predict the electrochemistry and mechanics of SSBs. In this study, high-resolution focused ion beam-scanning electron microscopy tomography was used to investigate the microstructure of cathodes composed of a nickel-rich cathode active material (NCM) and a thiophosphate-based inorganic solid electrolyte (ISE). The influence of the ISE particle size on the microstructure of the cathode was visualized by 3D reconstruction and charge transport simulation. By comparison of experimentally determined and simulated conductivities of composite cathodes with different ISE particle sizes, the electrode charge transport kinetics is evaluated. Porosity is shown to have a major influence on the cell kinetics and the evaluation of the active mass of electrochemically active particles reveals a higher fraction of connected…

Calendar aging of Li-ion batteries with Si/graphite electrodes was investigated within this study. A total of 121 single-layer pouch full cells with either graphite or Si/graphite (3.0 wt−%, 5.8 wt−% and 20.8 wt−% Si) anodes and NMC622 cathodes with the same N/P ratio were built on pilot-scale. Calendar aging was studied at SoC 30%, 60%, and 100%, as well as temperature (25 °C, 45 °C, 60 °C) and time dependence. The aging data was analyzed in terms of capacity fade and a square-root behavior was observed. Differential voltage analysis (DVA) has been performed as a function of aging time. The observed temperature and time dependence is best described by time dependent, 3D Arrhenius plots. Post-Mortem analysis (SEM, EDX, GD-OES) is applied to investigate the changes on electrode and material level. Conclusions are drawn on the main aging mechanisms for calendar aging of Li-ion cells with Si/graphite anodes and differences between Si/graphite and pure graphite anodes are discussed. The Si-containing cells show a combination of lithium inventory loss and a loss of accessible Si active…

This study introduces an easy and efficient ultrasonic-assisted approach for the preparation of mesoporous praseodymium cerate (MS-Pr2Ce2O7) by employing maltose as a novel and eco-friendly capping agent. Some techniques such as field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used for the characterization of nanoparticles. For the detection of carbendazim (CBZ), a new electrochemical sensor based on the modified screen-printed electrode (SPE) has been presented. The modification of the electrode surface was made using praseodymium cerate. Cyclic voltammetry (CV) has been utilized to study the electrochemical behavior of the MS-Pr2Ce2O7/SPE and better electrochemical performance was observed compared to bare SPE for the oxidation of CBZ. The optimization of pH and accumulation time was done. Under optimized conditions (pH = 7 and accumulation time:160 s), the oxidation peak currents that responded to CBZ concentration between 0.01 and 175.0 μM exhibited a linear relationship (R2 = 0.9977), and the…

The impact of mechanical pressure on electrode stability in full-cells comprising microscale silicon-dominant anodes and NCA cathodes was investigated. We applied different mechanical pressures using spring-compressed T-cells with metallic lithium reference electrodes enabling us to analyze the electrode-specific characteristics. Our investigation covers a wide pressure range from 0.02 MPa (low pressure - LP) to 2.00 MPa (ultra high pressure - UHP) to determine the optimal pressure for cyclic lifetime and energy density. We introduce an experimental methodology considering single-component compression to adjust the cell setup precisely. We characterize the cells using impedance spectroscopy and age them at C/2. In the post-mortem analysis, cross-sections of the aged anodes are measured with scanning electron microscopy. The images are analyzed with regard to electrochemical milling, thickness gain, and porosity decrease by comparing them to the pristine state. The results indicate that cycling at UHP has a detrimental effect on cycle life, being almost two-fold shorter when compared…

The slow electrochemical reaction kinetics of artificial graphite is one of the limiting factors for safety of lithium-ion batteries, especially the lack of systematic research on activation energies of various kinetic processes. In this work, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic intermittent titration technique (GITT) were used to investigate key kinetic parameters of artificial graphite such as solid-state Li + diffusion coefficient ( D Li+ ) and activation energy. The results reveal the evaluation of the chemical diffusion coefficient of same material is independent of the technique and shows a similar value, with D Li+ ranging from 10 −11 to 10 −13 cm 2 ·s −1 . The activation energies measured by EIS and GITT for solid-state Li + diffusion in graphite at 50% depth of discharge are 74.5 kJ·mol −1 and 66.8 kJ·mol −1 , which are in the same order of magnitude as the activation energies of charge transfer resistance (59.5 kJ·mol −1 ), electrode/electrolyte interface membrane impedance (56.1 kJ·mol −1 ), and ohmic impedance (6.6…

Electrochemical machining (ECM) is an efficient and precise manufacturing technology with broad prospects for numerous applications. As a subset of electrochemical machining, electrochemical polishing (ECP) is an advanced surface finishing method that utilizes electrochemical principles to produce smooth and reflective surfaces on various materials, particularly metals. This process is distinguished by its ability to refine surfaces without causing scratches or other forms of mechanical damage, thereby providing a significant advantage over traditional mechanical polishing techniques. The high processing efficiency of ECP renders it particularly suitable for industries that demand large-scale production and high-quality surface finishes. This work reviews the fundamental aspects of ECP, comparing three mechanisms: viscous film theory, salt film theory, and enhanced oxidation–dissolution equilibrium theory. Furthermore, it examines the factors influencing the effectiveness of ECP, including electrolyte composition, temperature, electropolishing time, voltage, and current.…

The anode overhang is usually cited to prevent lithium plating at the cell edges of lithium-ion batteries. Still, numerous reports in the literature show lithium plating at the cell edge, which is typically referred to as edge plating. Edge plating is often attributed to inhomogeneous lithium distribution, thermal gradients, or pressure-dependent effects. This work presents an easy-to-implement two-dimensional electrochemical model demonstrating inhomogeneous lithiation induced by the anode overhang, which can explain experimentally observed edge plating. First, the mechanism of inhomogeneous lithiation due to the anode overhang is explained in detail. Then, a parameter study on charge protocol and geometric cell properties is presented, and the implications for cell applications are analyzed. Finally, the findings are discussed and put into a broader perspective of cell design, manufacturing, and fast charging application. In Part II of this work, the simulation is validated experimentally using multi-reference electrode single-layer pouch cells.

The burgeoning intersection of machine learning (ML) with electrochemical sensing heralds a transformative era in analytical science, pushing the boundaries of what’s possible in detecting and quantifying chemical substances with unprecedented precision and efficiency. This convergence has accelerated a number of discoveries, improving electrochemical sensors’ sensitivity, selectivity, and ability to comprehend complicated data streams in real-time. Such advancements are crucial across various applications, from monitoring health biomarkers to detecting environmental pollutants and ensuring industrial safety. Yet, this integration is not without its challenges; it necessitates navigating intricate ethical considerations around data use, ensuring robust data privacy measures, and developing specialized software tools that balance accessibility and security. As the field progresses, addressing these challenges head-on is essential for harnessing the full potential of ML-enhanced electrochemical sensing. This review briefly explores these dimensions, spotlighting the significant…

Lithium iron phosphate (LFP) battery cells are ubiquitous in electric vehicles and stationary energy storage because they are cheap and have a long lifetime. This work compares LFP/graphite pouch cells undergoing charge-discharge cycles over five state of charge (SOC) windows (0%–25%, 0%–60%, 0%–80%, 0%–100%, and 75%–100%). Cycling LFP cells across a lower average SOC results in less capacity fade than cycling across a higher average SOC, regardless of depth of discharge. The primary capacity fade mechanism is lithium inventory loss due to: lithiated graphite reactivity with electrolyte, which increases incrementally with SOC, and lithium alkoxide species causing iron dissolution and deposition on the negative electrode at high SOC which further accelerates lithium inventory loss. Our results show that even low voltage LFP systems (3.65 V) have a tradeoff between average SOC and lifetime. Operating LFP cells at lower average SOC can extend their lifetime substantially in both EV and grid storage applications.

LiMn x Fe 1−x PO 4 is a promising positive electrode material for Li-ion batteries. In order to understand the failure mechanisms of this material, LiMn 0.8 Fe 0.2 PO 4 /graphite pouch cells were cycled at 40 or 55 °C over three voltage ranges: 2.5–3.6 V (Fe plateau), 3.6–4.2 V (Mn plateau), and 2.5–4.2 V (full voltage range). Cells cycled at higher temperature and over the full voltage range had the highest capacity fade. Differential voltage analysis showed that cells cycled over the Mn plateau and full voltage range had the highest Li inventory loss, and there was no active mass loss in any of the cells. Micro X-ray fluorescence spectroscopy showed that cells with higher levels of Mn deposition on the negative electrode had higher Li inventory loss. Constant voltage storage experiments at 55 °C showed rapid capacity loss for cells held at top of charge. Despite having similar Li inventory loss trends to the cycled cells, there was less Mn deposition on the negative electrodes. Thus, the capacity fade mechanisms are different for cells that undergo cycling and storage.

Degradation models are important tools for understanding and mitigating lithium-ion battery aging, yet a universal model that can predict degradation under all operating conditions remains elusive. One challenge is the coupled influence of calendar and cycle aging phases on degradation mechanisms, such as solid electrolyte interphase (SEI) formation. In this work, we identify and systematically compare three different SEI interaction theories found in the literature, and apply them to experimental degradation data from a commercial lithium-ion cell. In a step-by-step process, and after careful data selection, we show that SEI delamination without any cracking of the active particles, and SEI microcracking, where cycling only affects SEI growth during the cycle itself, are both unlikely candidates. Instead, the results indicate that upon cycling, both the SEI and the active particle crack, and we provide a simple, 4-parameter equation that can predict the particle crack rate. Contrary to the widely-accepted Paris’ law, the particle crack rate decreases with increasing cycles,…

Physicochemical models of lithium-ion cells, like the Doyle Fuller Newman (DFN) model, are omnipresent in battery research and development as they provide crucial insight into the cell, while equivalent circuit models dominate the area of application-oriented models, where speed is paramount. In this work, we develop and analyze a model that combines the two approaches using equivalent circuits and the DFN theory. By using a generalized approach to equivalent circuits, we model the necessary electric and diffusional processes analogously. The developed model accounts for all physical processes and internal states contained in the standard DFN model. We investigate the impact of model discretization and compare the developed model to a reference DFN implementation. Agreement between the models for both the predicted cell voltage and internal states shows that the developed equivalent circuit model provides a physically meaningful description of a lithium-ion battery, thereby successfully combining the two main modeling approaches for lithium-ion batteries.

The advancement of electrode materials is essential for addressing the energy and biomedical challenges. A multi-functional approach was employed to create a new electrode material of cobalt oxide-embedded nitrogen-doped porous graphene (Co3O4@NpG) for sensing and energy storage applications. In the present study, we have fabricated a new electrochemical sensing platform based on Co 3 O 4 @NpG. The sensing performance and selective detection capability of the demonstrated sensor was optimized and tested by determining dopamine (DA), uric acid (UA), and ascorbic acid (AA) simultaneously in analyte fortified biological samples. The sensing response is noticed to be linearly dependent upon the concentration of AA, DA, and UA in the range of 0.1–450, 0.1–502, and 0.2–396 μM, respectively. This material also showed good electrochemical energy storage performance when assessed as a supercapacitor electrode. The Co 3 O 4 @NpG electrode material showcased a remarkable specific capacitance of 314.58 Fg −1 , an energy density of 10.06 Wh kg −1 at a power density of 240 Wkg −1 at 0.5 Ag −1 ,…

Lithium-ion batteries (LIBs) are widely chosen for energy storage owing to their high coulombic efficiency and energy density. Within the positive electrode materials of LIBs, the structural integrity of secondary particles, composed of randomly oriented single-crystal primary particles, is crucial for sustained performance. These particles can fracture as a result of both mechanical stress and chemical interactions within the solid. Modelling LIBs is a complex task involving electro-chemo-mechanical phenomena and their interactions on different length scales. This study proposes a numerical modeling framework to investigate the active particle degradation and its impact on electrochemical performance. The model integrates mechanical and electrochemical processes, tracking crack evolution and mechanical failure through phase field damage. The coupled time-dependent non-linear partial differential equations are solved in a finite element framework using COMSOL Multiphysics. The model offers numerical insights into intergranular and transgranular fracture within secondary particles.…

Lithium metal battery (LMB) technology is very attractive as it has the potential to offer energy densities greater than 1000 Wh L −1 . A thorough investigation of cell performance against various vehicle operational requirements is required for the successful deployment of this technology in practical electric vehicle applications. For instance, there have been several reports on the high reactivity of Li metal with electrolyte leading to continuous electrolyte consumption in LMB. Due to these parasitic reactions, electrolyte dries out and Li metal morphological changes occur leading to reduced cycle life of lithium metal batteries. In contrast, there are also claims of stable and long cycle life of LMB in several publications, although most of the results were obtained in coin cells. In this report we will take a closer look at the LMB cell to understand its performance and manufacturability. Our goal is to investigate and provide a thorough report on advances and challenges starting from the cell level down to component design of LMB.

One of the most powerful spectroscopic tools for battery analysis is X-ray photoelectron spectroscopy (XPS); however, its great power, must be accompanied by great responsibility for authenticity. Fluorine is documented to be unstable under XPS conditions, and fluorinated salts used in Li batteries show photodecomposition. As all-solid-state batteries advance, demand for surface characterization is increasing. Here, a popular solid polymer electrolyte comprising a fluorinated salt in a PEO matrix was measured by XPS. Rapid photodecomposition after few minutes produced mainly LiF, initially not found on the surface. Not being aware of such artifacts may lead to an erroneous analysis of the characterized electrochemical system.

In this investigation, we present a tailored one-dimensional photonic crystal sensor (1D PCS), magnesium oxide (MgO) and silicon dioxide (SiO2) layers designed for the specific detection of diseased blood samples components, including plasma, platelets, red blood cells, and uric acid concentrations. The sensor structure is architecturally optimized for 6, 8,10,12,14, and 20 periods, encapsulating a central defect cavity that facilitates the interaction with the blood samples. Upon introducing the blood samples into this cavity, the transmittance spectrum is meticulously analyzed using the transfer matrix method to observe the variations in the defect mode’s wavelength. The study is conducted over a range of incident waves from wavelength 450 to 750 μm, enhancing the understanding of the sensor’s effect on the detection mechanism. In this context, our sensor demonstrates a remarkable sensitivity of approximately 815 nm per refractive index unit (RIU-1). It achieves a detection limit of 10–5, showcasing an exceptional ability to detect low concentrations of the infected blood…

The calendar aging and self-discharge behavior of Na-Ion cells containing a layered oxide NaNi 1/3 Fe 1/3 Mn 1/3 (NFM) cathode were investigated and compared to two Li-Ion cell chemistries, G/LiFePO 4 (LFP) and SiG/LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811). The self-discharge measurements were performed via voltage hold experiments at different states of charge (10%, 40%, 50%, 70%, 90%, and 100%) and temperatures (25 °C, 40 °C and 55 °C). A high-precision coulometry analysis was conducted to investigate the coulombic efficiency (CE), differential voltage analysis (DVA), and end-point slippage. The results show that the Na-Ion cells present a similar self-discharge behavior to the NMC811 Li-Ion cells. In addition, via CE and end-point slippage analysis, strong reversible reactions were observed for the Na-Ion cells. Despite the poor CE values, the cells presented a low capacity loss. Post-mortem analysis showed sodium plating on the edges of all the SOCs investigated. The LFP results presented mainly calendar losses from lithium inventory loss with almost no cathode-related degradation. At…

Stress tests are developed that focus on anode catalyst layer degradation in proton exchange membrane electrolysis due to simulated start-stop operation. Ex situ testing indicates that repeated redox cycling accelerates catalyst dissolution, due to near-surface reduction and the higher dissolution kinetics of metals when cycling to high potentials. Similar results occur in situ, where a large decrease in cell kinetics (>70%) is found along with iridium migrating from the anode catalyst layer into the membrane. Additional processes are observed, however, including changes in iridium oxidation, the formation of thinner and denser catalyst layers, and platinum migration from the transport layer. Increased interfacial weakening is also found, adding to both ohmic and kinetic loss by adding contact resistances and isolating portions of the catalyst layer. Repeated shutoffs of the water flow further accelerate performance loss and increase the frequency of tearing and delamination at interfaces and within catalyst layers. These tests were applied to several commercial catalysts, where…

Lithium plating during fast charging of porous graphite electrodes in lithium-ion batteries accelerates degradation and raises safety concerns. Predicting lithium plating is challenging due to the close redox potentials of lithium reduction and intercalation, obscured by the nonlinear dynamics of electrochemically driven phase separation in hierarchical pore structures. To resolve dynamical resistance of realistic porous graphite electrodes, we introduce a model of porous secondary graphite particles to the multiphase porous electrode theory (MPET), based on electrochemical nonequilibrium thermodynamics and volume averaging. The resulting computational framework of “hierarchical MPET” is validated and tested against experimental data over a wide range of fast charging conditions and capacities. With all parameters estimated from independent sources, the model is able to quantitatively predict the measured cell voltages, and, more importantly, the experimentally determined capacity for lithium plating onset at fast 2C to 6C rates. Spatial and temporal heterogeneities in the…

The all-vanadium redox flow battery (VRFB) is widely regarded as the most effective solution for mitigating the intermittent nature of renewable energy sources and simultaneously achieving “carbon neutrality goals.” Nevertheless, the battery’s overall performance is adversely affected by capacity loss resulting from side reactions, hence constraining its viability for usage in large-scale energy storage systems. This study proposes a novel approach that aims to minimize side reactions and mitigate capacity fade by employing an appropriate charge cut-off voltage mechanism. The experiment centers around the examination of performance indicators, including battery charge/discharge capabilities, internal resistance, capacity retention rate, and efficiency, for analytical purposes. The findings indicate that by setting the charge cut-off reference voltage at 1.65 V, the battery’s capacity can be sustained at 61.76% after 60 cycles. When the charge cut-off voltage is raised by increments of 0.1 V and 0.15 V, the corresponding reductions in battery capacity amount to 1.74% and 5.16%…

Carbon-based electrocatalysts derived from zeolitic imidazolate framework-8 (ZIF-8) have garnered significant attention, owing to their structural advantages, high surface area, and tunable active sites. Herein, we report the synthesis of heteroatom sulfur (S) modified ZIF-8 derived carbon nanocages (ZnS@N/S-C) for oxygen electrocatalysis through self-assembly and two-step pyrolysis. The resultant ZnS@N/S-C exhibits catalytic activity towards oxygen reduction reaction (ORR) with high half-wave potential (0.86 V) and stability (91.4%), separately, which is comparable to or superior to Pt/C. Furthermore, the application of ZnS@N/S-C as a cathode for Zn-air batteries (ZABs) demonstrates performance metrics such as an open-circuit voltage of 1.407 V, a power density of 114.4 mW cm −2 , and a specific capacity of 764.6 mAh g Zn −1 , etc surpassing Pt/C. The performance of ZnS@N/S-C can be attributed to the fact that the introduction of S significantly increases the specific surface area, pore volume, and defect extent of the catalyst, while optimizing the electronic structure and…

We designed a bi-metallic Co-Ni/BTC/4,4′-BiPy metal organic frameworks (MOFs) as an electrode material for the electrochemical detection of epinephrine and nor-epinephrine. The bi-metallic MOFs were synthesized by a solvothermal method. Following this, the bimetallic MOFs were modified with BTC and amine rich 4,4′-BiPy to improve charge transfer kinetics through non-covalent π–π interaction. This modified electrode was employed as a sensing platform for the simultaneous electrochemical detection of epinephrine and nor-epinephrine. The MOFs modified platform exhibited a 10–50 μM linear range with a limit of detection of 0.724 μM ± 0.128 (N = 3) and 0.815 μM ± 0.124 (N = 3), a sensitivity of 0.583 and 0.505 μA μM−1 cm−2 corresponding to epinephrine and nor-epinephrine detection. Finally, the electrochemical sensor was tested in blood and urine samples spiked with known concentrations of epinephrine and nor-epinephrine. Results confirmed the usefulness of the proposed platform for the detection of epinephrine and nor-epinephrine in clinical samples.

Zoonotic diseases are a pressing challenge to global health, arising from their interspecies transmission and potential for pandemics. Conventional diagnostic methodologies often suffer from limitations in speed, sensitivity, and accuracy, underscoring the imperative for innovative solutions. Nanomaterial-integrated biosensors, especially in electrochemical modules, have gained increasing attention as promising tools for the rapid, sensitive, point-of-care and targeted detection of zoonotic pathogens. Despite considerable progress, pervasive challenges, including market fragmentation and research disparities, impede widespread adoption. This review explores the essential role of electrochemical biosensors in combating zoonotic diseases, underscoring the urgency for accessible, cost-effective, and high-throughput diagnostic platforms. It details the principles of electrochemical biosensing and highlights the role of diversified nanomaterials in enhancing the performance of biosensors. Furthermore, it examines the integration of nanomaterials with different electrodes and signal…

With sodium-ion batteries (SIBs) finding widespread application, the demand grows for hard carbon, the most popular anode material for SIBs. Hydrothermal carbonization facilitates the production of hard carbon with desired characteristics from various sources. Despite the considerable volume of literature addressing this subject, there is a notable absence of investigations elucidating the relationship between synthesis conditions and the electrochemical characteristics of the product. Here we study systematically the influence of hydrothermal carbonization parameters on hard carbon characteristics and emphasize the potential of hard carbon as an anode material for SIBs. The initial Coulombic efficiency (ICE) is significantly affected by the particle size of the glucose-derived hard carbon, which, in turn, depends on glucose concentration in the initial solution, pH, and stirring regime. By optimizing the hydrothermal carbonization parameters, the ICE up to 91% and a good reversible capacity of ∼300 mAh g −1 in a half cell are achieved. Full cells with Na 3 (VO) 2 (PO 4 ) 2 F…

This study explores the impact of simple electrolyte additives on the performance of layered oxide/hard carbon sodium-ion pouch cells. The cycle life of these cells between 2.0 and 3.8 V is assessed at various temperatures (20, 40, and 55 °C) with different solvent systems based on ethylene carbonate, diethyl carbonate, and dimethyl carbonate. A particular challenge in these cells is gas generation at high temperature. Pouch bag experiments which separate the charged electrodes to measure their gas generation from reactions with the electrolyte show that hard carbon generates no gas, but the sodium layered oxide produces large amounts of gas. Isothermal microcalorimetry corroborates these results with parasitic heat flow measurements of pouch bags and full pouch cells. A crosstalk mechanism is revealed which lowers gas generation and reduces parasitic heat flows in full cells. The electrolyte additives prop-1-ene-1,3-sultone, sodium difluorophosphate, and 1,3,2-dioxathiolane-2,2-dioxide (DTD) are effective at reducing gas generation and heat flow from the positive electrode. They…

Industry-standard diagnostic methods for rechargeable batteries, such as hybrid pulse power characterization (HPPC) tests for hybrid electric vehicles, provide some indications of state of health (SoH), but lack a physical basis to guide protocol design and identify degradation mechanisms. We develop a physics-based theoretical framework for HPPC tests, which are able to accurately determine specific mechanisms for battery degradation in porous electrode simulations. We show that voltage pulses are generally preferable to current pulses, since voltage-resolved linearization more rapidly quantifies degradation without sacrificing accuracy or allowing significant state changes during the measurement. In addition, asymmetric amounts of information gain between charge /discharge pulses are found from differences in electrode kinetic scales. We demonstrate our approach of physics-informed HPPC on simulated Li-ion batteries with nickel-rich cathodes and graphite anodes. Multivariable optimization by physics-informed HPPC rapidly determines kinetic parameters that correlate with…

This study reports the accuracy and applications of an attenuated total reflectance–surface-enhanced infrared absorption spectroscopy (ATR–SEIRAS) technique to indirectly measure the interfacial pH of the electrolyte within 10 nm of the electrocatalyst surface. This technique can be used in situ to study aqueous electrochemical reactions with a calibration range from pH 1–13, time resolution down to 4 s, and an average 95% confidence interval of 14% that varies depending on the pH region (acidic, neutral, or basic). The method is applied here to electrochemical nitrate reduction at a copper cathode to demonstrate its capabilities, but is broadly applicable to any aqueous electrochemical reaction (such as hydrogen evolution, carbon dioxide reduction, or oxygen evolution) and the electrocatalyst may be any SEIRAS-active thin film (e.g., silver, gold, or copper). The time-resolved results show a dramatic increase in the interfacial pH from pH 2–7 in the first minute of operation during both constant current and pulsed current experiments where the bulk pH is unchanged. Attempts to…

The combination of metal-organic frameworks (MOFs) and metal nanoparticles offers great prospects for improving the electrochemical properties of sensors. In this paper, silver (Ag) nanoparticle-doped metal-organic framework (MIL-101) composites (Ag-MIL-101) were prepared by ultrasonic treatment of MIL-101 and the reduction of the metal precursor (AgNO3) within the MIL-101 material. X-ray diffraction patterns confirmed the formation of Ag-MIL-101(Cr). The resulting material was used to construct a new electrochemical sensor for the reliable detection of dopamine. The electrochemical response of the developed sensor toward dopamine was evaluated using differential pulse voltammetry. A Box-Behnken design was performed, and response surface methodology was used to study the influence of different parameters on dopamine detection. The response of the modified electrode for dopamine detection was linear in the range from 0.02 μM to 10 μM, and the detection limit was 0.02 μM (S/N = 3). Additionally, it showed high selectivity in the presence of urea, uric acid, ascorbic acid, and…

Cervical cancer (CC), a significant contributor to the mortality of females globally, manifests an annual incidence of 500,000 cases and is predominantly linked to the human papillomavirus (HPV) infection. The pressing demand for affordable and user-friendly assays for CC detection is highlighted by the limited availability and dependability of diagnostic screening tools, especially in developing countries. In response to the critical need for enhanced cervical cancer diagnostics, we present an innovative electrochemical immunosensor designed for the selective detection of the HPV 16-E7 oncoprotein. The immunosensing platform is constructed from a gold-graphitic carbon nitride (Au-g-C 3 N 4 ) nanocomposite, with antibodies immobilized through a physical adsorption process onto the sensing platform. Employing Square Wave Voltammetry (SWV), we systematically evaluated the antigen-antibody interaction, achieving ultrasensitive detection of E7 with ferric/ferrocyanide. The linear detection range of the proposed sensor for E7 antigen is 0.01 fg ml −1 to 1 ng ml −1 , assuming ideal…

Calendering of battery electrodes is a commonly used manufacturing process that enhances electrode packing density and therefore improves the volumetric energy density. While calendering is standard industrial practice, it is known to crack cathode particles, thereby increasing the electrode surface area. The latter is particularly problematic for new Ni-rich layered transition metal oxide cathodes, such as NMC811, which are known to have substantial surface-driven degradation processes. To establish appropriate calendering practices for these new cathode materials, we conducted a comparative analysis of uncalendered electrodes with electrodes that have a 35% porosity (industrial standard), and 25% porosity (highly calendered) for both single crystal (SC) and polycrystalline (PC) NMC811. PC cathodes show clear signs of cracking and decrease in rate capability when calendered to 25% porosity, whereas SC NMC811 cathodes, achieve better cycling stability and no penalty in rate performance at these high packing densities. These findings suggest that SC NMC811 cathodes should be…

Uric acid (UA) is an important biomarker in blood to diagnosis diseases linked with hyperuricemia. Although several detection methods exist for UA sensing, electrochemical method has emerged as a promising alternative. For effective performance of a biosensor, the choice of electroactive material plays a crucial role. The developed electrodes are enzymatic and non-enzymatic with modified nano-structures of metal oxides, ferrites and carbon-based materials. Several combinations of nanocomposites using metal oxides with carbon-based compounds show promising results for biosensor applications. This is attributed to its functional groups, higher surface area and porous nature that can improve the sensing performance as it requires only quick-time processing with inexpensive and direct detection methods. The electrochemical method uses anodic peak current which is the analytical signal to sense the electrochemical oxidation of UA. This technique paves a new way to make electrodes for point-of-detection devices in near future. It could be the next generation of non-invasive analysis for…

In this population driven society, the major cause of environmental pollution is due to modern agricultural practices & intensified industrialization. These kind of economic practices leads to excessive deposition of residual pesticides, heavy metals in both soil and water. This is a commonly accepted agreement that there is an immediate need for qualitative and quantitative information on environmental entities. Electrochemical sensing platforms which offers in situ and rapid detection of wide range of pollutants gives good results compared to other conventional methods. “Graphene” a wonder material possessing excellent physiochemical properties when utilized as an electrode for sensing, enables quicker diffusion of target analytes and detects environmental contaminants even at trace levels. The main motive of the manuscript is to give some new insights on graphene based electrochemical sensors on detecting some environmental entities like pesticides, heavy metals & antibiotics. It also highlights the growth & performance of the sensors over the years in detecting these hazardous…

The advancement of cost-effective and ultra-stable hydrogen evolution reaction (HER) electrocatalysts is critical in addressing carbon dioxide emission challenges. Because of their promising catalytic properties, excellent stability, along with diversity in phases, nickel phosphide-based nanomaterials are viewed as prospective candidates for HER. This review begins with an examination of nickel phosphide synthetic routes, including vapor−solid reaction, solution−phase, and electrochemical deposition. Next, the process of hydrogen generation from water electrolysis was comprehensively explained, and various hetero-nanostructures, including nickel phosphides/-metal phosphides, -metal hydr(oxides), and the other materials for HER are shown. Finally, existing challenges and feasible advice for the progress of nickel phosphide-based electrocatalysts for hydrogen generation were highlighted.

The volumetric capacity of typical Na-ion battery (NIB) negative electrodes like hard carbon is limited to less than 450 mAh cm −3 . Alloy-based negative electrodes such as phosphorus (P), tin (Sn), and lead (Pb) more than double the volumetric capacity of hard carbon, all having a theoretical volumetric capacity above 1,000 mAh cm −3 in the fully sodiated state. These alloy materials have massive volume expansion, with P expanding by almost 300% and both Sn and Pb expanding to about 400% of their initial volumes when fully sodiated. This work shows that despite this large volume change, Sn and Pb have excellent half-cell cycling performance, including high Coulombic efficiency. A blended P-hard carbon cell shows promising initial performance despite P having far lower electronic conductivity than either Sn or Pb. Overall, it is expected that these Na-alloying elements will be needed to increase the volumetric energy density of NIBs to compete with low-cost lithium iron phosphate-based cells. In fact, one company, UNIGRID, has recently demonstrated cylindrical Na-ion cells that use…

Li-ion battery graphite electrodes form a solid-electrolyte-interphase (SEI) which is vital in protecting the stability and efficiency of the cell. The SEI properties have been studied extensively in the context of formation and additives, however studying its kinetic features after formation have been neglected. In this study we show the dynamic resistive behavior of the SEI after formation. Via electrochemical impedance spectroscopy measurements on Cu-foil after SEI formation we show how the SEI shows a potential-dependent resistance which can be explained by a change in charge carriers (Li+) in the SEI. Additional measurements on graphite exhibit a similar behavior and allow us to separate the charge transfer kinetics from the SEI resistance, showing that the SEI resistance is the dominating resistance in the graphite kinetics. Measurements on pre-formed electrodes also show how the SEI resistance changes when in contact with electrolyte of different LiPF6 salt concentrations, with the resistance decreasing for increasing salt concentrations. Ultimately, we show that the SEI…

Single crystal NMC640/artificial graphite cells balanced for low voltage operation (≤4.1 V) and using electrolyte salts rich in lithium bis(fluorosulfonyl)imide are demonstrated to have exceptional lifetime during continuous operation at 100 °C. Cells tested to an upper cutoff voltage of 4.0 V retained >80% of their original capacity for 600 cycles and 4300 h at 100 °C and 1200 cycles and 1 year cycling to 3.9 V at 85 °C. The cells exhibited minimal gassing, no transition metal dissolution from the positive electrode, and no detectable corrosion of the aluminum current collector. Ultra-high precision coulometry measurements from 20 to 100 °C suggest an Arrhenius-type relationship for the coulombic inefficiency and capacity fade of these cells. The possibility of exploiting this relationship to project ambient temperature lifetime from high-temperature measurements is suggested. However, cell performance at the highest temperatures is most likely reduced by the permeation of electrolyte through the seals of the pouch cell.

Sodium-ion batteries (SIBs) represent a great opportunity for stationary storage, back-up power supply and light electric vehicle applications. Energy and power requirements for these applications needs to be satisfied. Beside material improvement, electrode microstructure plays a critical role. Herein, the influence of hard carbon (HC) particle size and mass loading on the rate performance have been comprehensively investigated. This work analyses the relative contribution of ionic resistance within the porous electrode (R ion ) in SIB full cells employing relevant mass loadings. R ion was obtained by applying electrochemical impedance spectroscopy (EIS) to symmetrical cells and by fitting a transmission line model (TLM) under “ blocking ” conditions. The relative contribution of R ion arising from HC electrodes was further compared to the charge transfer resistance (R CT ) in full cell configuration utilising a three-electrode cell under “ non-blocking ” conditions. Results illustrate mass loading to be as far more influential on cell rate performance compared to the two particle…

Biosensors-on-chip (BoC), compact and affordable public diagnostic devices, are vital for preventing health crises caused by viral and bacterial mutations, climate change, and poor diets. Clinical, remote, and field use are possible with these devices. BoC is used in food safety, environmental monitoring, and medical diagnosis. The coupling of tunneling magnetoresistance (TMR) sensing elements in chip form with surface functionalized iron oxide nanoparticles (IONPs) as a biomarker, known as TMR/ IONPs, allows BoC devices to be made. The functional framework of BoC based on TMR/ IONPs, the instrument system, and biomolecule immobilization will be covered in this review. This review aims to overview the recent research on a biosensor using TMR technology with IONPs biomarkers and discuss its future advances in point-of-care diagnostics. TMR sensors have revolutionized low-magnetic field sensing technologies, yet biosensing faces challenges. However, it’s important to recognize that TMR sensors exclusively utilize out-of-plane connections. that creates a larger separation between…

The imperative shift towards decarbonization necessitates the production of clean hydrogen through water electrolysis, powered by renewable energy sources. Among electrolyzer technologies, proton-exchange-membrane (PEM) systems emerge as a promising option for large-scale hydrogen generation due to their modular design and rapid response, aligning well with the intermittency of renewable energy. In this study, we employ a tape casting method to fabricate microporous layers (MPLs), both as a single layer and as a bilayer over commercial porous transport layers (PTLs), to further enhance performance of water electrolyzers. We demonstrate that microporous layers require adequate pore sizes to facilitate gas removal, preventing gas flooding and preserving electrolyzer performance. Our single layer microporous layers exhibit lower overpotentials compared to commercial sintered Ti PTLs by 142 mV at 4 A·cm⁻ 2 . Moreover, we show that having an effective microporous layer enhances electrolyzer performance irrespective of the substrate used, offering avenues for cost reduction. We also…

Tailored design of carbon supports and their pore morphologies is crucial to achieve the ambitious durability and performance targets for future proton exchange membrane fuel cells (PEMFCs). We compared platinum catalysts supported on solid Vulcan carbon, porous Ketjenblack carbon, and accessible porous modified Ketjenblack carbon in a voltage cycling-based accelerated stress test (AST) with frequent intermittent characterizations. We derived how catalyst morphologies affect cell performance and electrochemical properties (electrode roughness factor, ORR activity, oxygen transport resistances) at beginning-of-life (BoL) and in various states of degradation up to 200,000 voltage cycles. We confirmed the enhanced Pt surface area retention of porous carbon-supported catalysts, ascribed to well-shielded Pt particles in internal pores, but find that this comes at the expense of lower initial high current density performance already at BoL. Accessible porous carbon-supported catalysts with wider pores mostly retain those durability benefits while, simultaneously, maximizing H2/air…

Olivine-type lithium iron phosphate (LFP) is used widely as a cathode material with excellent cycling stability, thermal stability, and low cost for lithium-ion batteries in power vehicles and energy storage. However, it has inherent drawbacks that limit its further development, such as low electronic conductivity and lithium ion diffusion rate. Here, secondary spherical particles LFP-W/Ti@C were synthesized using a simple sanding and spray drying method. The pyrolysis of glucose forms a uniform and dense amorphous carbon on the surface of LFP, and the constructed three-dimensional conductive network accelerates the transfer of electrons and ions while mitigating the volume expansion during the lithiation-delithiation process. In addition, the synergistic co-doping of W/Ti achieves nanosizing of primary particles with more active sites providing locations for lithium ions storage, while reducing polarization and internal resistance and enhancing the diffusion kinetics of lithium ion. The LFP-W/Ti@C obtained after optimization still has a discharge capacity of 107.7 mAh g −1 (with a…